Aerosol dispensers are well known in the art. Aerosol dispensers typically comprise an outer container which acts as a frame for the remaining components and as a pressure vessel for propellant and product contained therein. Outer containers made of metal are well known in the art. However, metal containers can be undesirable due to high cost and limited recyclability. Attempts to use plastic have occurred in the art. Relevant attempts in the art to employ plastic in aerosol dispensers are found in U.S. Pat. Nos. 2,863,699; 3,333,743 and 2009/0014679.
The outer containers are typically, but not necessarily, cylindrical. The outer container may comprise a bottom for resting on horizontal surfaces such as shelves, countertops, tables etc. The bottom of the outer container may comprise a re-entrant portion as shown in U.S. Pat. No. 3,403,804. Sidewalls defining the shape of the outer container extend upwardly from the bottom to an open top.
The open top defines a neck for receiving additional components of the aerosol dispenser. The industry has generally settled upon a neck diameter of 2.54 cm, for standardization of components among various manufacturers, although smaller diameters, such as 20 mm, are also used. Various neck shapes are shown in U.S. Pat. Nos. 6,019,252; 7,303,087 and 7,028,866.
Typically a valve cup is inserted into the neck. The valve cup is sealed against the neck to prevent the escape of the propellant and loss of pressurization, such as described in commonly assigned U.S. Pat. No. 8,869,842 or as described in U.S. Pat. No. 8,096,327. The valve cup holds the valve components which are movable in relationship to the balance of the aerosol dispenser.
For example, a non-aerosol system using an elastically deformable band may be used as described in commonly assigned U.S. Pat. No. 8,631,970. Such a system may dispense a personal care product. Pistons for an aerosol container are disclosed in U.S. Pat. Nos. 3,433,134; 3,827,607; 4,234,108; 5,127,556; and 8,245,888. Other piston devices are shown in U.S. Pat. Nos. 3,312,378; 3,756,476; 4,641,765; 4,913,323; 4,703,875; 5,183,185; 6,230,943; 6,588,628; 6,745,920; 7,225,839; 8,088,085. An elevator with a screw is disclosed in commonly assigned U.S. Pat. No. 5,000,356.
Aerosol dispensers, having a valve cup and movable valve components, may comprise different embodiments for holding, storing, and dispensing product used by the consumer. In one embodiment, the product and propellant are intermixed. When the user actuates the valve, the product and propellant are dispensed together. This embodiment may utilize a dip tube. The dip tube takes the product and propellant mixture from the bottom of the outer container. This embodiment may be used, for example, to dispense shaving cream foams.
Or, a collapsible, flexible bag may be sealed to the opening on the underside of the valve cup or may be placed between the valve cup and the container. This bag limits or even prevents intermixing of the contents of the bag and the components outside of the bag. Thus, product may be contained in the bag. Propellant may be disposed between the outside of the bag and the inside of the outer container. Upon actuation of the valve, a flow path out of the bag is created. This embodiment is commonly called a bag on valve and may be used, for example, in dispensing shaving cream gels. An aerosol container having a bag therein may be made from a dual layer preform, having plural layers disposed one inside the other. Relevant attempts in the art include U.S. Pat. Nos. 3,450,254; 4,330,066; 6,254,820; RE 30093 E; WO 9108099 and US 2011/0248035A1.
But aerosol container having a bag on valve or dip tube configuration are not well suited to dispense high viscosity products. High viscosity products occur in many forms, such as mousse, toothpaste, caulk, shave gel, body lotion, shampoo, antiperspirant, etc.
A piston configuration may be suited for high viscosity products, and may be used for atomizing aerosol executions as well. In a piston aerosol dispenser, a movable piston is juxtaposed with the bottom of the outer container. As the user operates the actuator, propellant under the piston provides motive force to advance the piston, towards the top of the container, thereby dispensing product.
But, piston dispensers require a bung hole or one way valve in the bottom of the container, for propellant fill and subsequent sealing. But the bung holes and valves provide a path for leakage.
But if the bung hole and valve are eliminated over leakage concerns, a conventional piston dispenser needs egress for air trapped during assembly. If trapped air is not accounted for, full piston travel may not occur. Relevant attempts include U.S. Pat. Nos. 6,343,713; 6,708,852; 7,182,227; 7,225,839; 8,353,845 and 8,905,271.
Accordingly, a new approach is needed.